1. In this scoping review of preoperative risk assessment tools for elective noncardiac surgery, cardiopulmonary exercise testing (CPET) was the most assessed tool, particularly with regard to predictive validity.
2. Most tools did not have strong evidence for reliability, pragmatic qualities, or validity compared with CPET.
Evidence Rating Level: 2 (Good)
Study Rundown: Preoperative risk assessment allows for patients at risk of post-operative complications to be identified and participate in shared decision making. Multiple forms of preoperative risk assessment currently exist, but each has benefits and drawbacks, and clinical guidelines internationally are not concordant on the preferred method. This study aimed to describe the body of evidence for various preoperative risk assessment tools for elective noncardiac surgery. Of the 243 studies explored, most looked at the gold standard cardiopulmonary exercise testing (CPET), while others examined the field walking test, climbing test, and stress test, among other methods. CPET was the most studied tool for reliability, but unstructured interviews had greatest number of participants overall. Of all performance-based tools that were compared with CPET, field walking test were the best studied; for questionnaires specifically, the Duke Activity Status Index (DASI) had the strongest evidence. The quantity of evidence regarding predictive validity was highest for CPET and field walking tests among performance-based tests. Among self-reported tools, the unstructured assessment had the most evidence. Notably, only CPET had evidence on clinical utility. Most studies had a population that was heavily composed of older adults, with minimal studies exploring patients with obesity, arthritis, or other disability. The generalizability of this study was limited by the fact that it was based on reported data without requests for missing data. In summary, CPET remains the most studied and validated tool; while field walking tests and DASI are the most commonly used alternatives, there remains significant uncertainty about their clinical utility, particularly among people with baseline disability.
Click to read the study in AIM
Relevant Reading: Ventilatory efficiency as a prognostic factor for postoperative complications in patients undergoing elective major surgery: a systematic review
In-Depth [scoping review]: This study examined different tools for preoperative risk assessment in elective noncardiac surgery and assessed their performance. Inclusion criteria were tools to measure risk of post-operative complications, participant age above 18 years, and elective noncardiac surgery. Randomized studies, cohort studies, field testing studies, and quality improvement reports were included. Exclusion criteria included cardiac surgeries, lung and liver transplants, and minor ambulatory procedures with their own preoperative measures. Performance measures that were studied included reliability, concurrent criterion validity (how much the tool agrees with the gold standard), and predictive validity. The study synthesized information from 243 studies with a total of 76,567 participants; studies were largely from high-income countries (n = 206; 84.8%) and from Europe or Central Asia (n = 132; 54.3%). A total of 26 unique tools were assessed, of which 21 were performance-based and 5 based on self-reported measures. CPET provided the most evidence on reliability, which was reported by 10 studies with a total of 406 participants. The tool with the most participants was the unstructured interview, for which 1 study obtained reliability data from 4879 participants. Predictive validity was assessed in a large proportion of studies (n = 223; 91.8%), with cardiorespiratory complications (n = 107; 48.0%) and general complications (n = 100; 44.8%) being the most common outcomes. Evidence of predictive validity was strongest for CPET (114 studies, 31,047 participants), followed by field walking tests (53 studies, 8871 participants). Evidence for clinical utility was found only for CPET (6 studies, 938 participants), with the most common end point being health care utilization (n = 5, 83.3%). Pragmatic qualities were examined in 77 studies; CPET was the performance-based test with the most evidence (43 studies, 7501 patients), while DASI was the only self-reported assessment with any evidence (2 studies, 220 patients). Overall, this study provided a comparison of existing preoperative risk assessment tools and helped provide direction for future research into less frequently used tools, especially among specific patient populations.
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